Respiratory weakness in neuralgic amyotrophy: report of two cases with phrenic nerve involvement

Abstract

An isolated affection of the phrenic nerve is a rare feature in patients with neuralgic amyotrophy. We report 1 case each of bilateral and unilateral phrenic neuropathy. The first patient presented a sudden onset of severe respiratory failure without pain. The second patient developed intense pain in the neck and in the right shoulder followed by dyspnea on mild effort and orthopnea. Chest X-rays showed elevation of the diaphragm. Needle electromyography revealed denervation restricted to the diaphragm. The phrenic nerve conduction was within the normal range. The diagnosis of neuralgic amyotrophy may be particularly difficult when the palsy of the phrenic nerve appears without brachial plexus involvement or the typical shoulder pain of acute onset. In our patients, electrophysiological evaluation combined with radiographic studies, ventilatory parameters and biochemical analyses were helpful in establishing the diagnosis.

Extensive brain calcification and dementia in postsurgical hypoparathyroidism

“…This presentation should be contrasted with the majority of reports on bilateral phrenic neuropathies, which are commonly described within the setting of immune brachial plexus neuropathy or ParsonageTurner syndrome. [1][2][3] One large series suggests that phrenic neuropathy occurs unilaterally in about 6% and bilaterally in 1% of immune brachial plexus neuropathies, 4 but these cases generally have pain, upper limb weakness, and a tendency to recover with time. There are a number of reports that specifically describe isolated bilateral phrenic paralysis in immune brachial plexus neuropathy, but the association with pain has also been characteristic.…”

“…There are a number of reports that specifically describe isolated bilateral phrenic paralysis in immune brachial plexus neuropathy, but the association with pain has also been characteristic. [1][2][3]5 In fact, we were only able to find two prior descriptions of painless bilateral phrenic neuropathy. In one, respiratory difficulty began 6 weeks after a liposuction procedure and recovered a few months later.…”

“…Current literature generally describes this presentation in the setting of arm weakness with neck or shoulder pain, often occurring after infectious illness or surgery. [1][2][3] It follows that these factors have led authors to place this phenomenon within the spectrum of immune brachial plexus neuropathy. [1][2][3][4] In contrast, bilateral isolated phrenic neuropathy (BIPN) unaccompanied by pain, arm weakness, or antecedent events has not been emphasized as a distinct entity.…”

“…[1][2][3] It follows that these factors have led authors to place this phenomenon within the spectrum of immune brachial plexus neuropathy. [1][2][3][4] In contrast, bilateral isolated phrenic neuropathy (BIPN) unaccompanied by pain, arm weakness, or antecedent events has not been emphasized as a distinct entity. In contrast to immune brachial plexus neuropathy, this painless involvement may be difficult to recognize and distinguish from other neuromuscular disorders with similar respiratory symptoms and signs.…”

Brachial neuritis masquerading as acute coronary syndrome

“…Neuralgic amyotrophy can lead to diaphragmatic paralysis. Isolated involvement of the phrenic nerve is a rare feature in patients with neuralgic amyotrophy [2]. We report a case of brachial neuritis with bilateral phrenic nerve involvement leading to dramatic dyspnoea, orthopnoea and paradoxical breathing.…”